Pulverizing or grinding mill



April 1, 1930. D. J. UHLE ET PULVERIZING OR GRINDING MILL Filed Nov. 22, 1928 2 Sheets-Sheet 1 INVENTORfi DAV) J. UH LE By JOSEPH V DURNIN ATTORNEY.

April 1-, 1930 D. .1. UHLE ET AL PULVERIZING 0R GRINDING MILL 2 Sheets-Sheet 2 Filed Nov. 22, 1928 I INVENTOR.5 DAV\D J. UHLE,

By JOSEPH VT DURMN;

MWMW

A TTORNEY.

Patented Apr. 1, 1 930 UNITED STATES FE-REL PULVERIZING on GRINDING MILL Application as November 22, 1928.: Serial No. 321366.

Our invention relates to improvements in pulverizing or grinding mills, and has particular reference to-improvements in the rotatable pushing means, which serves to drive the grinding balls. In accordance with our invention, a rotatable yoke is provided which is secured to and driven by the usual drive shaft. This yoke has outwardly projecting arms, preferably formed integral therewith. These arms have their central longitudinal axes off center with respect to the yoke and preferably substantially parallel with tangents to the yoke; This arrangement is preferred, whereby there will be suflicient space. forthe grinding balls. j Each arm carriesan arm-extension, pivoted thereto, and preferably arranged in end-to-end relation to the same. A spring is confined between portions of the arm and 59 arm-extension, to oppose the swinging movement of the arm-extension in a direction opposite to the direction of travel of the yoke. A pusher element is preferably rotatably mounted upon the arm-extension, so that it is adapted to turn upon its longitudinal axis,

during its rotation with the yoke. This pusher element slidablyi contacts with the adjacent grinding ball, and its contact face is spherically curved and convex, or tapers forwardly, to co-act therewith. By having the pusher element yieldingly supported, undue strains and hammering action between the pusher element and the ball, is eliminated, particularly upon starting the mill, and liability of the arms of the yoke being broken off also eliminated, which frequently occurs where the pusher elements are rigidly carried by the arms. The yielding support for the pusher element also permits'of a more free rotation of the grinding ball. Further,

the pusher element being rotatable upon its axis, the contacting surfaces between the pusher element and the grinding ball are constantly shifting and wearing or scoring of the grinding ball or pusher element are greatly reduced. As the grinding ball moves out slightly, due to the wearing down of the grinding ring, the contacting surfaces of the pusher element and grinding ball automati- 5 cally adjust themselves, without injury to the contacting parts, which is rendered possible,

to a considerable extent, by the rotation of the pusher element upon its axis. The minimum contact surfaces between the grindingv ball and pusher element, alsopermits of the free restricted radial movements 7 of the grinding ball due to the shifting'of the ball 1 by the varying thicknesses of the material being ground;

In the accompanying drawings, forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same, V

Figure 1 is a central vertical longitudinal section through a mill embodyingour invention, I

Figure 2 is a horizontal section taken'on line 2'2 of Figure 1,- v

Figure 3 is a longitudinal section-taken on line '33of Figure 2, j I. g r Figure 4 is a plan view of theyoke and associated elements,

Figure 5 is a side elevation of the same, Figure 6 is an enlarged plan-view of'one of the arms and arm extension and associated elements,

7 Figure 7 is a plan view of thesame, and, Figure 8 is a transverse section taken on line 8-8 of Figure 6. I

The pushing means or yoke and associated elements constituting the principal feature of the present invention, are particularly well adapted for use in connection with the pulverizing or grinding mill, shown in Letters Patent No. 922,468, granted under date of i May 25', 1909, to J. VV.'Fuller, Jr. Thismill embodies generally a casing 10, within which is arranged a grinding ring 11, having a transversely curved annularrecess12, within which travel the grinding balls 14. An upper casing section 15 is arranged-upon the casing 10 and a screen 16 is disposedwithin the casing section 15 and spaced therefrom, with a coarser protecting screen 17, disposed inwardly of the first named screen. The pulverized or ground material which passes the screen 16 discharges into a passage 18, and descends through the passage 19 and finally discharges through an outlet 20. The numera121 designates a feed hopper, which discharges the material into the upper portion of the casing 15, inwardly of the screen 17. The numeral 22 designates a vertical drive shaft, journaled in bearings 23 and 24, and driven by a pulley 25. The construction thus far described is identical with that shown in Patent N 0. 922,468, above referred to, and is thought to be sufiicient for a proper understanding of the present invention.

Our improved pushing means or yoke embodies a tubular "hub 26, arranged .upon the drive shaft 22, to rotate therewith. Extending outwardly from the hub 26 are arms27, preferably formed integral therewith The longitudinal axes of these arms are off-center with respect to the hub 26, and are 1 preferably parallel with tangents to the hub.

This arrangement is preferred, to provide sufiicient space for thegrlnding balls, as

will be apparent. Each arm27 is provided in its forward face with a recess 28, for receiving therein an apertured knuckle 29, preferably formed integral with an arm-extension 30. The knuckle forms with the arm -extension shoulders 31'. The knuckle 29 r is apertured, for receiving a pivot pin 32, also passing through openings 33, formed in the sides of thearm 27. The arm-extension- 30 is provided with a rearwardly projecting overhanging circumferentially extending head 34, integral therewith, and carrying 'aninwardly projecting lug 35, preferably integral therewith. Aco-acting lug 37 is carried by the circumferentially extending part of the arm 27, disposed opposite the head 34, and is preferably formed integral therewith, and arranged opposite the lug 35. The arm-extension 30 and its head 34 are arranged in end-toend relation to the arm 27, as shown. A suitably stifi compressible substantially radial coil spring 36 is disposed rearwardly of the arm-extension and confined between the end of the arm 27, and the over hanging head 34, with the retaining lugs and 37 passinginto the ends thereof. t is thus seen that the action of the circumferentially extending head 34 retains the radial spring 36 in place, and there is no tendency for the spring. to partake of lateral displacement due to centrifugal force. e

The numeral 38'designates' a pusher element, which is adapted to rotate upon its axis and be bodily rotated by the rotating yoke, F or this purpose, thepusher element 38 is provided with a cylindrical shank 39 preferably formed integral therewith, and

this shank is rotatably 'mounted within a cylindrical recess or opening 40 formed in the forward'side-of the arm-extension 30. The'pusher element 38 is arranged to engage with the adjacent grinding ball 14, and this grinding ball is confined between the pusher element and; the next forward arm 27. There A is aslightclearance between the ball and the adjacent forward arm 27, whenthe ball is tending in an elevation travel of the vertical centrifugal blade contacting with the pusher element, and the mill is in operation, but this clearance is not sulficient to permit the shank 39 to be withdrawn from the recess 40, or to permit the arm-extension 30 swinging forwardly sufiiciently, to free the spring 36. The forward swinging movement of the arme:-:tension 30 is also limited by the shoulder 31 contacting with the end of the arm 27, and the clearance between this shoulder and the end of the adjacent arm is the same as the clearance between the grmding bail and the adjacent forward arm, as explained.

The forward contacting end of the pusher element 38 is preferably spherically curved and convex, or tapered forwardly, and this convex surface slidably contacts with the grinding ball. The pusher element 33 is preferably formed ofsteel and has itscenvex contacting face hardened. As illustrating one way in which the hardening may be effected, wercontemplate placing a covering 41 of high speed tool steel upon the pusher element, which may be welded thereto, al-

though the convert face may be hardened by any suitable means, 7 By virtue of the convex or tapered face .of the pusher element, the minimum contact surface is afforded between the pusher element andthe grinding ball, and this permits of t 1e free spinning of the grinding balkand this s, ning action ofthe ball is aided by the yield. lg support of the pusher element."

The numeral 45 designates ing outwardly projecting radial lugs 47, bolted to the arm's'44, as shown at 48. Formed integral with the ring 46 are spacedvertical arms 49, carrying upper vertically arranged blades or paddles 50, integral therewith. The blades are disposed at'the leading edges of the vertical arms 49 and are further connected therewith by tapered webs 51, interal therewith. The vertical blades 530 ro- Z) i tate adjacent to the screens 16 and 1'? and .14 and serve to raise the-powdered or ground material, which is brought into the path of and-thrown thereby toward the screen 16.

In operation of the mill, the material is fed into the central portion of the same through the hopper 21, and passes to the grinding v a fan or blower as a whole, including a lower ring 46, carrythe pusher elements.

balls 14, traveling upon the grinding ring. The shaft 22 is driven at a suitably high speed, and the elevating blades serve to draw the ground or powdered material upwardly and through the same into the path of travel of the vertical or centrifugal blades 50, which in turn throw the same toward or through the screens 16 and 17. The grinding balls are propelled by the pusher elements 38. These balls rotate rapidly upon the grinding'ring, and must be free to turn or spin. The free action of the grinding balls depends greatly upon the area of contact between the same and It is desired to have these areas of contact reduced to the minimum, and for this reason the contact faces of the pusher elements are convex.

It is to be understood that the form of our invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts, may be resorted to without departing from the spirit of our invention, or the scope of the subjoined claims.

Having thus described our invention, we claim V 1. In a grinding mill, a casing, a grinding ring arranged within the casing, grinding balls operating upon the grinding ring, a drive shaft extending between the grinding balls, pusher elements having convex ball engaging surfaces spherically curvec n all directions, and a support carrying the pusher elements and driven by the shaft.

2. In a grinding mill, a casing, a grinding ringarranged within the casing, grinding balls operating upon the grinding ring, a rotatable support arranged within the casing, and pusher elements rotatably mounted upon the support to turn upon their axes with relation thereto and having convex ball engaging surfaces spherically curvedin all directions.

3. In a grinding mill, a casing, a grinding ring arranged within the casing, grinding balls operating upon the grinding ring, a rotatable support arranged within the casing, and pusher elements rotatably mounted upon the support to turn upon their axes with rela tion thereto and varranged to contact with the grinding balls, the-longitudinal axes of the rotatable pusher elements extending circumferentially of the support. I

4. In a grinding mill, a casing, a grinding ring arranged within the casing, grinding balls operating upon the grinding ring, a rotatable support arranged within the casing, generally radial yielding supporting devices carried by the rotatable support, and separate pusher elements rotatably mounted upon the yielding supporting devices and arranged to contact with the grinding balls, saidpusher elements having their axes of rotation extending generally circumferentially.

5. In a grinding mill, a casing, a grinding ring arranged within the casing, grinding balls operating upon the grinding ring, a drive shaft extending between the grinding balls, a yoke carried by the drive shaft and embodying outwardly extending arms, armextensions pivotally connected with said arms, springs arranged between portions of the arms and arm-extensions and separate rotatable pusher elements carried by the armextensions for engagement with the grinding balls;

6. In a grinding mill, a casing, agrinding ring arranged within the casing, grinding balls operating upon the grinding ring, a drive shaft extending between the grinding balls, a yoke carried by the drive shaft and embodying generally radially c extending arms, generally radially extending arm-extensions arranged in end-to-end relation to said arms and having pivotal connection therewith to swing in the plane of rotation of said arms, said arm-extensions having circumferentially extending heads, generally radially disposed compressible coil springs arranged between the circumferentially (ex-1 tendlng heads and said arms, and pusher elements carried by the forward side ofsaid arm-extensions.

7 In a grinding mill, a casing, a grinding ring arranged within the casing, grinding balls operating uponthe grinding ring, a drive shaft extending between the grinding balls, a yoke carried by the drive'shaft and embodying generally radially extending arms, said arms having-recesses formedr therein, generally radially arm-extensions ar ranged in end-to-end relation to said arms and having knuckles extending into said recesses, means pivotally connecting the knuckles and said arms, circumferential heads carriedbythe arm-extensions and arranged upon the rear side thereof, lugs carried-by the heads and said arms, generally radial compressible coil springs arranged between the heads and said arms and receiving the lugs in the opposite ends thereof, and a pusher element carried by the forward side of each arm-extension. 7 8. In a grinding mill, a casing, a grinding ring arranged within the casing, g balls operating upon the grinding ring, a

drive shaft extending between the grinding halls, a yoke carried by the drive shaft and embodying outwardly extending arms, said arms having recesses formed therein,arm-

extensions arranged in end-to-end relation to said arms and having knuckles extending into said recesses, means pivotally connecting the knuckles and said arms, overhanging heads carried by the arm-extensions and arranged, upon the rear side thereof, lugs carried by the heads and said arms, compressible coil springs arranged between the heads and said arms and receiving lugs in the opposite ends thereof, and a pusher element rotatably rinding 1511 mounted upon the arm-extension and arranged to engage the adjacent grinding ball. 9.111 a grinding mill, a casing, a grn ring'arranged Within the casing, grinciing balls operating upon the grii ling ring, a drive shaft extending between the grinding balls, a yoke carried by the shaft and embodying outwardly extending arms, said arms having recesses formed therein, armextensions arranged in end-to-end relation to said arms and having knuckles extending into said recesses, means pivotally con necting the knuckles and said arms, overhanging heads carried by the arm-extensions and arranged upon the rear thereof, lugs carried by the heads and said arms, compressible coil springs arranged between the heads and said arms and recei -ing gs in the opposite ends thereof, and a pn er element rotatably mounted upon the arm-extension and having a convex face to engage with the adjacent grinding ball.

10. In a grinding mill, a casing, a horizontal grinding ring withinthe casing, grinding balls engaging the ring, a lion mentally rotating support, pusher elements pivotally mounted upon the support to swing horizontally with relation thereto and engaging a the grinding balls, and yielding means to oppose the swinging movement of the pivoted pusher elements in one direction. 11. In a grinding mill, a casing, a hori- Zontal grinding ring within the casing, grinning balls engaging the ring, a horizontally rotating support, pusher elements pivotally mounted upon the support to swing horizontally with relation thereto engaging the grinding balls, said pusher elements havingforwardly tapered faces for providing a small area of contact with the balls, and springs for opposing the rearward swinging movement of the pusher elements upon their pivots.

12. In a grinding mill, a casing, a grim ing ring within the casing, grinding balls operating upon the grinding ring, a rotatable support, and pusher elements carried by the rotatable support and having convex ball engaging surfaces spherically curved in all directions so that they will afford the minimum contact areas with the grinding balls.

18. In a grinding mill, a casing, a grinc ing ring within the casing, grinding balls operating upon the grinding ring, a rotatable support arranged within the casing, pivoted arms carried by the support, springs to oppose the swinging movement of the arms upon their pivots, and pusher elements carried by the 7 arms and provided with forwardly tapering contact surfaces" for engagement with the balls, said forwardly tapering contact surfaces co-acting with the spring-pressed pivoted arms for effecting a spinning movement ofthe balls.

14:. In a grinding mill, a casing, a grinding convex contact faces to engage with the grinding balls, said convex contact faces coacting w1th the pivoted spring-pressed arms to effect a spinning movement of the balls.

15. In a grinding mill, a casing, a grind- 7 ing ring within the casing, grindin balls engaging the ring, a rotatable support within the casin arms aivoted to the sua aort springs to oppose the'movement of the arms upon their pivots, and pusher elements carried by the pivoted arms and having convex faces which are harder than the body portion of the pusher elements, said convex contact faces co-acting with the spring-pressed pivoted arms to efieot spinning movement of the balls.

16. In a grinding mill, a casing, a grinding ring within the casing, grinding balls engaging the ring, a rotatable support within the casing, generally radial arms pivoted to the support to swing in the plane of rotation of the support, resilient means to oppose the swinging movement of the arms, and pusher elements rotatably mounted upon the forward side of the arms and having their axes of rotation extending circumferentially I having circumferentially extending headsdisposed opposite the parts of said arms, generally radial springs held between said parts and the cireumferentially extending heads, and pusher elements arranged upon the forward sides of the arm extensions and pivoted thereto so that their axes of rotation extend generally circumferentially, said pusher elements having convex contact faces to engage 'ith the balls.

In testimony whereof we aflix our signatures.

DAVID J. UHLE.

JOSEPH V. DURNIN. 

